#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
const int N = 1010;
int f[N], a[N];
int n;
int main()
{
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    int res = -2e9;
    for (int i = 1; i <= n; i++)
    {
        f[i] = a[i];
        for (int j = 1; j < i; j++)
        {
            if (a[j] < a[i]) f[i] = max(f[i], f[j] + a[i]);
        }
        res = max(res, f[i]);
    }
    cout << res << endl;
    return 0;
}